I went with my wife to Vassiliki using Neilson, for a couple of weeks one September - god it was 8 years ago 
My wife chose to do the sun lounging bit while I did the riding. I more or less had the guide to myself for the 2 weeks, along with a nice Orange full-susser. Great weather, really relaxing despite my wife suffering from sun-stroke
The riding isn't overly technical, lots of double-tracks/donkey tracks with plenty of climbing, but good fun in the sun. I guess it might have changed since I was there, though?